This tag is for questions about noise. In signal processing, noise is a general term for unwanted (and, in general, unknown) modifications that a signal may suffer during capture, storage, transmission, processing, or conversion.
Questions tagged [noise]
231 questions
3
votes
1 answer
Radius and amplitude of kernel for Simplex noise
I'm wondering if formulas exist for the radius and amplitude of the hypersphere kernel used in Simplex noise, generalized to an arbitrary number of dimensions. Ideally I'd like an answer with two equations in terms of n (number of dimensions) that…
Void Star
- 2,555
2
votes
0 answers
Choosing Non-linear Filter for Noisy Sensor Data
I have a sensor whose trends I am attempting to analyze. The sensor samples values periodically from a system, but is subject to measurement disruptions of certain types. Visually, I know what the trend should look like, but I need to automate the…
Ben W.
- 21
1
vote
0 answers
Why the axes of principal components rotate towards outliers?
What is the reason for rotation of the axes of the principal components towards high variance noise?
user188541
- 11
1
vote
1 answer
Is the range of perlin noise [-1, 1] for any pseudo-random set of unit vectors?
In perlin noise, four pseudo-random unit vectors are placed at each corner of a 1 by 1 square.
Let's denote each pseudo-random vector $\vec{v_1}, \vec{v_2}, \vec{v_3}, \vec{v_4}$
Then, the perlin noise function should look like $[0, 1] \times [0, 1]…
Cedric Martens
- 1,288
1
vote
0 answers
Cubic 3d perlin noise function?
I would like to make some 3d procedural architecture with isosurfaces, so i need to make space into cubic wall shapes and then to subdivide each wall into intricate grids, bars, diamond patterns etc.
Can someone tell me some mathematic tricks to…
bandybabboon
- 301
1
vote
0 answers
How to get noise percentage?
So I don't really know if this is the right place to ask, but I hope so..
Let's say I have a function $h$ and I want to make a test on the influence of noise over this function. What I have done is having
$\tilde{h} = h + n$
where $n \sim N(0,…
Quang Thinh Ha
- 115
0
votes
1 answer
Remove unlogical points (noise) in a curve
I have a time serie with 1000 values, but some values are out of logic.
Let's say I have points like that:
[[...]100,101,100,99,97,103, 10,5,2, 100,101,102,97[...]]
(there are much more value in the time series) But how to remove this "noise"…
Unitech
- 105
0
votes
0 answers
Noise function guaranteed to have unique values inside a certain limit
Is there any formula to produce a coherent noise, where it is guaranteed that no 2 unique values will be present inside any subset of size s ?
Dávid Tóth
- 133
0
votes
0 answers
Coherent Noise function producing dissimilar results for similar inputs
Is there a noise function I(x,y) which produces dissimilar output for similar inputs?
The primary purpose of it would be to mask coordinates so any point could have a unique value inside the given range.
Dávid Tóth
- 133
0
votes
1 answer
White noise RMS vs. its bandwidth
From numerical simulation and regression analysis I discovered that the root-mean-square amplitude of white noise with bandwidth $\Delta\!f$ is proportional to $\sqrt{\!\Delta\!f}$.
How can this be derived mathematically ?
Petoetje59
- 165
0
votes
1 answer
identifying noise in a set of numbers
Say I have a set of numbers:
1, 3, 2, 1, 1, 20, 1, 3, 75, 86
I'd like to filter out all the small numbers, or "noise" in the set. The values 75 and 86 are so much higher than everything else (even 20) that I can drop everything but the 75 and 86.
A…
Stéphane
- 101